Foam arrestor for mixing machine



Oct. 27, 1964 L. BALASSA FOAM ARRESTOR FOR MIXING MACHINE 2 Sheets-Sheet 1 Filed Jan. 25. 1961 INVENTOR.

Oc't. 27, 1964 L. BALASSA 3,154,296

FOAM ARRESTOR FOR MIXING MACHINE Filed Jan. 25. 1961 2 Sheets-Sheet 2 IN V EN TOR.

United States Patent 3,154,296 FOAM ARRESTOR FOR MIXING MACHINE Leslie L. Balassa, Creighton Lane, Scarborough, N.Y. Filed Jan. 25, 1961, Ser. No. 84,820 4 Claims. (Cl. 259-95) This invention relates to an improved mixing machine for use in the preparation of liquid emulsions, such as pigment dispersions, and is generally similar to the type of machine shown and described in my co-pending application Ser. No. 84,821, filed January 25, 1961. The invention particularly relates to means needed for mitigating objectionable foaming incidental to the mixing of liquids of low viscosity that are therefore of a watery nature.

It is a primary object of the invention to effectively alleviate such foaming which otherwise interferes with the efiiciency of the mixing operation of the machine. Other advantages of the invention are hereinafter set forth in the following speification and accompanying drawings.

Referring to such drawings,

FIG. 1 is a side elevation of a mixing machine showing an embodiment of the invention;

FIG. 2 is an enlarged, fragmentary, sectional view of the foam-arresting structure;

FIG. 3 is an enlarged, sectional view of the operating head of the machine and an associated part of the foamarresting device;

FIG. 4 is a top plan view of the same; and

FIG. 5 is a sectional view on the line 5-5 of FIG. 3.

Referring to FIG. 1, the mixing machine is shown as having a motor 10, a motor support 11 adjustably mounted by means of a tubular rod 12, and bracket 13, on an upright post 14 anchored in a pedestal 15. A circular series of guide rods 16 depend from motor support 11, and are attached at their lower ends to an operating head 20 extending within a container 21 (dotted lines) beneath the top level, indicated in dotted lines 22, of a fluid solution to be mixed by the machine.

The motor has a drive shaft 25, and beneath in vertical alignment therewith is a driven mixer shaft 26. The adjacent ends of said shafts are connected by a suitable crenelated coupling 27.

Operating head 20 (FIGS. 3 and 4) comprises a stator 30 and a turbine rotor 40 positioned directly below it. Stator 30 is formed with a central hub 33, and a plurality of radial spokes 34 having their outer ends separated, and within which hub the lower end of shaft 26 is journalled and thereby stabilized. A cylindrical open-ended stator sleeve 60 is detachably secured to the outer ends of suitable spokes 34, as by the bayonet lock indicated, and provides a housing for the rotor so that the fluid being mixed will surge upwardly through the openings between the spokes, and the head will operate as a closed turbine mixer. By removing the sleeve the head will then operate as an open turbine mixer.

As shown in FIG. 5, rotor 40 consists of a plurality of electric-fan-type flat blades 50 radiating from an integral central disc 51, and having an angular pitch adapted to rapidly and continuously circulate the liquid solution in the container through stator sleeve 60, and since the rotor is directly driven by the motor, there is a resulting high degree of turbulence present in the container in order to thoroughly mix its contents. A baffle plate 90 is suitably positioned above operating head 20, and is effective to deflect horizontally the material surging through the head so that the circulation referred to will be established as indicated by the arrows in FIG. 1.

The high turbulence within container 21 tends to cause the aforesaid objectionable foaming around the revolving mixer shaft, and at the top surface 22 of the liquid.

Means are provided to alleviate such foaming comprising, in part, a ringlike sleeve surrounding a portion of the lower end of mixing shaft 26. Sleeve 95 is held in a non-rotatable and fixed vertical position by a narrow band 96 which surrounds sleeve 95 and is adapted to be adjustably clamped to one of the rods 16. Sleeve 95 is advantageously made of open cellular spongelike material, which is capable of containing and substantially immobilizing the liquid within its structure in order to be both self-lubricating with respect to the rotating shaft 26 and to have the effect of suppressing the tendency of the liquid to foam when shaft 26 revolves within it. The liquid contained within cellular sleeve 95 lubricates shaft 26 rotating within sleeve 95 reducing friction and removing heat formed. Sleeve 95 operates to prevent the outer surface of shaft 26 from rotatably disturbing the liquid otherwise exposed to such action, and which is the cause of foaming developing in this region. However, when the head 20 is used as an open turbine mixer, the sleeve 95 will only operate successfully if the container 21 is provided with suitable known bafliing arrangements effective to prevent a vortex forming in the liquid being mixed.

Sleeve 95 is effectively positioned in container 21 vertically by moving band 96 up or down the rod 16 to which it is adapted to be clamped so that the upper end 97 of sleeve 95 will be slightly above the normal level of the liquid, and its lower end 98 will be well below the surface of the liquid, but spaced from stator sleeve 60 to provide for the required free circulation therethrough.

Foaming at the upper level 22 of the liquid may also be mitigated by the use of a flat pliable disc 1G0 operatively mounted to rest on the surface of the liquid and, as indicated in broken lines in FIG. 1, follow its turbulence; and is inherently buoyant or caused to be buoyant particularly at its periphery. It may be secured at its center to the sleeve 95 by a thirnble 101 tightly fitted thereto. Disc 100 may be made of pliable buoyant material of which sheet polyethylene plastic is an example, not intended to limit or preclude the use of other suitable materials. It may also be made of pliable material, such as rubber, of a non-buoyant nature, which is rendered buoyant by an added buoyant ring attached to its perimeter, or it may be made to ride loosely along sleeve 95 when suspended by cords secured to its rim depending from the upper edge of container 21 so that it will rest on the surface of the liquid and be free to follow its turbulence. Preferably it is supported in the manner described and shown in the drawings.

Disc 100 blankets the top surface of the liquid and thereby tends to quiet surface turbulence. It also constitutes a shield effective to prevent a supply of air from coming into direct contact with the surface of the liquid, air being a constituent of the foaming action.

It will be understood that other applications of the principles disclosed herein are possible, and therefore are to be considered within the scope of the appended claims.

I claim:

1. A mixing device having low foaming characteristics during mixing of material within a container comprising a mixing head for operation Within said container, said mixing head comprising a stator and a rotor, remote drive means for said rotor, a shaft connecting said drive means to said rotor, means for preventing rotation of said stator, and foam arresting means comprising a sleeve of porous, absorbent structure journaled on and shorter than said shaft, and means non-rotatably supporting said sleeve on said shaft and spaced from said shaft ends so that a portion of said sleeve extends above and below the level of the material being mixed.

2. A mixing device for mixing material within a container with low foaming action comprising a mixing head for operation within said container, said mixing head comprising a stator and a rotor, remote drive means for said rotor, a shaft connecting said drive means to said rotor, means for coupling said stator to said drive means preventing relative rotation therebetween, and foam arresting means comprising a cylindrical sleeve of open mesh absorbent structure journaled on and shorter than said shaft, said sleeve absorbing said material and being self-lubricating for allowing free rotation between said sleeve and said shaft, and means non-rotatably supporting said sleeve along said shaft and spaced from said sleeves ends and connected to said stator coupling means, said sleeve being supported so that a portion thereof extends above and below the level of the material being mixed.

3. A mixing device for mixing material within a container with low foaming characteristics comprising a mixing head for operation within said container, said mixing head comprising a stator and a rotor, remote drive means for said rotor, a shaft connecting said drive means to said rotor, and foam arresting means comprising a pliable disc surrounding said shaft and having a surface generally perpendicular to the axis of said shaft, said disc being buoyantly supported on the material being mixed so as to generally float on the surface of said material and being of a diameter slightly smaller than the diameter of said container so as to cover substantially the entire top surface of the material in said container and means preventing rotation of said disc.

4. A low foaming mixing device for mixing material Within a container comprising a mixing head for operation Within said container, said mixing head comprising a stator and a rotor, remote drive means for said rotor, a shaft connecting said drive means to said rotor for preventing rotation of said stator, and foam arresting means comprising a combination of a cylindrical sleeve of open mesh absorbent structure surrounding a portion of said shaft between its ends and extending above and below the surface level of the material being mixed, means connected to said sleeve for preventing rotation with said shaft, said sleeve absorbing said material for self- 7 lubrication with said shaft, and a pliable disc coupled References Cited in the file of this patent UNITED STATES PATENTS Seburger Oct. '18, 1949 OTHER REFERENCES Germany, Sch. 7,381, printed Apr. 26, 1956 (K1. IVc 12c). 

1. A MIXING DEVICE HAVING LOW FOAMING CHARACTERISTICS DURING MIXING OF MATERIAL WITHIN A CONTAINER COMPRISING A MIXING HEAD FOR OPERATION WITHIN SAID CONTAINER, SAID MIXING HEAD COMPRISING A STATOR AND A ROTOR, REMOTE DRIVE MEANS FOR SAID ROTOR, A SHAFT CONNECTING SAID DRIVE MEANS TO SAID ROTOR, MEANS FOR PREVENTING ROTATION OF SAID STATOR, AND FOAM ARRESTING MEANS COMPRISING A SLEEVE OF POROUS, ABSORBENT STRUCTURE JOURNALED ON AND SHORTER THAN SAID SHAFT, AND MEANS NON-ROTATABLY SUPPORTING SAID SLEEVE ON SAID SHAFT AND SPACED FROM SAID 